Alito refused to say that Row vs Wade was settled law. He's refused to disavow his writings (from the 1980s) in which he said it should be overturned. He used to belong to an alumni group whose purpose was to keep women and people of color out of his alma mater. He was so proud of this membership, he used to put it on job applications. Maybe he's mellowed out and maybe he hasn't, but he won't even say what Justice Roberts said.
Write your congress person! Also, write a letter to the editor! Yes, your congressperson's staffers check your name off a list and dutifully ignores you (write the email anyway). They also pay attention to letters in newspapers, which can also sway the newspapers themselves. So do both. How to write the SF Chronicle. They want 200 words or less. Say you oppose him and say why and that's it. You can send the same letter to your two senators and your local paper.
If you write the same letter to a bunch of newspapers, that's called astroturfing, which is considered dishonest and bad. And people at right wing think tanks are doing it right now to support Alito. Make sure to use an address local to the newspaper which you write.
Californians should note that Senator Dianne Feinstein is on the committee so make sure to drop her a line: http://feinstein.senate.gov/email.html